Modification of Magnetic Graphene Oxide By An Earth-Friendly Deep Eutectic Solvent To Preconcentrate Ultratrace Amounts Pb(II) In Oil Seeds

The aim of this article is presenting an earth-friendly deep eutectic solvent (DES) to preconcentrate ultratrace amounts of Pb(II) prior to its quantification by flame atomic adsorption spectroscopy. The synthesis of adsorbent started by preparing graphene oxide according to the modified Hammer’s method, followed by magnetization by Fe3O4 nanohemispheres. Magnetic graphene oxide was dispersed in a mixture of LiCl and urea at 60° via ultrasonication. All the materials are environmentally-friendly and the preparation strategy is energy efficient. X-ray diffraction, scanning electron microscopy, alternating gradient force magnetometer and Fourier-transform infrared spectroscopy were applied to characterize the products. Graphene oxide has a large surface area and could be functionalized with DESs through π-π interaction and electrostatic force. Urea has active negative sites, which garb heavy metals due to the interaction between negative and positive agents. Accordingly, this adsorbent (UreaLiCl-mGO) could be offered as a capable adsorbent to preconcentrate ultratrace amounts of Pb(II). Conditions were optimized, and under the optimum situation, (a) limit of detection of 99 × 10-8 g L-1, (b) relative standard deviation (n=5) of 1.3%, (c) preconcentration factor of 100 (d) linearity of dynamic range of 5.0 × 10-6 – 23 × 10-6 g L-1, (e) durability of 6 months and (f) reusability of 7 times prove applicability of the adsorbent. The tests of selectivity, effect of interference ions, swelling property, isotherm of adsorption, kinetic of adsorption and thermodynamic of adsorption were completely investigated. Four different oil seeds were successfully applied as real samples.

Experimental Evaluation of Oil Extraction from South African Melia azedarach Seeds as Feedstock for Biodiesel Synthesis

Global increase in fuel prices and the associated problem of harmful emissions from combustion of fossil fuels has necessitated the need for more energy sources to sustain energy security and mitigate the negative environmental implications from the continuous use of petroleum diesel. This research is primarily focused on the production of biodiesel from Melia azedarach oil, which has not been much explored as a feedstock for diesel substitute. In consideration of the nutritional demands for edible oil seeds, the use of edible vegetable stock to produce biodiesel raises major ethical concerns with non-edible oil seeds presenting more feasible solution to energy crises. Oil was extracted from Melia azedarach seeds by exploring both mechanical and chemical methods. Biodiesel was produced from the extracted oil via alkali alcoholysis. An innovative Ultraviolet-Visible Spectroscopy (UV-VIS) was adopted as a process tracking mechanism for biodiesel production. An oil yield of 4.32% of crude oil was extracted using n-hexane under an extraction time of 24h and temperature of 55°C. Esterification parameters of 45:1 Molar concentration of alcohol to oil, reaction temperature of 53°C, a reaction time of 50 mins and concentrated sulphuric acid weight fraction of 5% gave a free fatty acid conversion of 89.37%. Based on the results obtained, the seed oil has been established as a promising feedstock with promising efficiency for biodiesel production. However, large scale extraction of oil from the seed for industrial production of biodiesel must be further investigated.